1422. Maximum Score After Splitting a String ---E

Given a string s of zeros and ones, return the maximum score after splitting the string into two non-empty substrings (i.e. left substring and right substring).

The score after splitting a string is the number of zeros in the left substring plus the number of ones in the right substring.

 

Example 1:

Input: s = "011101"
Output: 5 
Explanation: 
All possible ways of splitting s into two non-empty substrings are:
left = "0" and right = "11101", score = 1 + 4 = 5 
left = "01" and right = "1101", score = 1 + 3 = 4 
left = "011" and right = "101", score = 1 + 2 = 3 
left = "0111" and right = "01", score = 1 + 1 = 2 
left = "01110" and right = "1", score = 2 + 1 = 3

Example 2:

Input: s = "00111"
Output: 5
Explanation: When left = "00" and right = "111", we get the maximum score = 2 + 3 = 5

Example 3:

Input: s = "1111"
Output: 3

 

Constraints:

• 2 <= s.length <= 500
• The string s consists of characters '0' and '1' only.

A:

class Solution {
public:
    int maxScore(string s) {
        int n = s.length();
        vector<int> V0(n,0), V1(n, 0); // V0 is inclusive, and v1 is not 
        int c0 = 0;
        for(int i =0;i<n;i++){
            char ch = s[i];
            if(ch == '0'){
                c0++;
            }
            V0[i] = c0;
        }
        int c1 = 0;
        for(int i = n-1; i>=0; i--){
            char ch = s[i];
            V1[i] = c1;
            if(ch =='1')
                c1++;
        }
        int res = -1;
        for(int i =0;i<n-1;i++){
            res = max(res, V0[i] + V1[i]);
        }
        return res;
    }
};